Microgaps and Demineralization Progress around Composite Restorations

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Caries Research

Background:

• Marginal integrity of dental restorations is crucial for preventing secondary caries.
• Adhesive systems play a key role in achieving a seal between the tooth and restorative material.
• Understanding demineralization at restoration margins is essential for improving restoration longevity.

Purpose of the Study:

• To investigate the influence of different dental adhesives and marginal sealing on demineralization progression.
• To evaluate the efficacy of fluoride-releasing adhesives in inhibiting demineralization.
• To correlate initial marginal gap size with demineralization progression.

Main Methods:

• Bovine incisors were restored with four adhesive systems (Clearfil SE Protect, Bond Force, Scotchbond Universal, G-Bond Plus) and a flowable composite.
• Optical coherence tomography (OCT) was used to measure initial marginal gaps.
• Specimens underwent artificial saliva incubation, thermal cycling, and a 5-week demineralization challenge.
• Lesion progression was monitored weekly using OCT.

Main Results:

• Adhesive type and initial gap size significantly affected demineralization in enamel and dentin.
• Fluoride-releasing adhesives (SP, BF) demonstrated significantly slower enamel lesion progression.
• Initial marginal gaps were positively correlated with lesion size, particularly in enamel.
• Clearfil SE Protect, Bond Force, and Scotchbond Universal showed smaller initial gaps compared to G-Bond Plus and the control.

Conclusions:

• Microgaps at restoration margins significantly contribute to demineralization.
• Adhesive choice influences marginal sealing and subsequent demineralization.
• Fluoride release from adhesives may mitigate demineralization progression, suggesting benefits for caries prevention.